This is an R21 proposal in direct response to the announcement PA-04-006, "Neurotechnology, Research, Development, and Enhancement". This proposal addresses the request in the PA related to "development of novel tools and approaches for the study of the development, structure and function of the brain" including "those used for clinical assessment, diagnosis and treatment of brain disorders". As stated under "SPECIAL REQUIREMENTS" in the announcement, applications "may be design-, problem-, need-, or hypothesis-driven ". The current proposal is driven by the need for tools that can provide early effective and functional treatment of several categories of patients e.g. those with spinal cord and brain injuries including stroke as well as neurological diseases such as Parkinsonism. Furthermore, hip fractures, a common consequence of falls, seriously affect mobility and often leads to early death, especially in the elderly population. Current research has demonstrated in these populations of patients that gait training using partial body weight support (BWS) on a treadmill improves walking better than training with full weight bearing. One problem with the BWS technique that is not commonly acknowledged is that the harness supporting the subject decreases the need for a natural postural control. The harness provides an external support partly eliminating associated postural adjustments that are required during independent gait. We propose to build a tool that can further refine the concept of BWS training by allowing natural associated postural adjustments directly in the BWS training. We have demonstrated that upright balance function improves after training in a 90 deg tilted visual environment with the subject in a supine position strapped to a device (freely moving on air-bearings, cf. puck on an air hockey table) with a G-like load provided by a weight stack. For movements in the frontal plane, the tilted room environment allows associated postural adjustments, required in an upright environment, to occur. A video of a subject exercising in this environment appears to a blinded viewer as being upright with normal frontal plane postural adjustments and balancing against gravity. We propose to design, build and test a portable version of the tilted room concept that can be used in a hospital/clinical setting. Instead of a physical room subjects will view two 3-D automultiscopic displays representing windows to a virtual environment that may be captured from sites decided by the patient. In addition to treatment, the device can be used as a research tool to study postural control mechanisms The investigators represent a multidisciplinary team of experts from biomedical, computer engineering and the rehabilitation and exercise sciences.